Key facts
- Setting thermostats a few degrees higher when away from home balances energy efficiency and comfort.
- Adjusting thermostats by 7-10 degrees Fahrenheit for eight hours a day can save up to 10% annually on heating and cooling.
- In humid climates, turning off AC for long periods increases the risk of mold.
- Leaving AC off for hours and turning it back on can lead to wear and more frequent repairs.
- Smart thermostats can learn occupancy and adjust temperature, potentially saving 10% on cooling costs.
Experts suggest that the most effective strategy for saving energy and money on air conditioning involves adjusting the thermostat a few degrees higher when leaving home, rather than turning the unit off completely for extended periods. This approach balances comfort, humidity control, and system wear.
According to the U.S. Department of Energy, adjusting thermostats by 7-10 degrees Fahrenheit for eight hours daily can lead to annual savings of up to 10% on heating and cooling costs. However, the optimal strategy can vary significantly based on climate. In dry regions like Arizona, allowing the home to warm up more is feasible. Conversely, in humid areas such as Florida, turning the AC off for long durations can exacerbate indoor dampness and increase the risk of mold growth, as the system plays a role in moisture control.
Patrick Phelan, a mechanical engineering professor, noted that a 1-degree Fahrenheit increase in the thermostat can yield approximately 3% in cooling cost savings. He also cautioned that repeatedly turning AC systems off and on can lead to increased wear and tear, as units take 15 to 30 minutes to reach peak efficiency. The effectiveness of any strategy also depends on the building's insulation; homes with heavy materials like concrete or brick retain cool air longer than older, draftier structures.
The type of air conditioning unit also influences energy savings. Window units are generally less efficient due to potential air leaks. Experts suggest simple, low-cost improvements like using foam spray insulation in drafty areas. Smart thermostats offer a convenient solution by learning occupancy patterns and automatically adjusting temperatures, potentially saving around 10% on cooling costs compared to manual thermostats.
Beyond thermostat settings, simple measures like blocking sunlight by closing blinds can significantly impact indoor temperatures. Opening windows at night, when temperatures drop, can also help cool homes, though this is more effective in dry climates where it doesn't introduce excess moisture. Some blinds are designed to reflect sunlight, and tinted window films are another option to reduce solar heat gain.